Human gut bacteria, such as member of the Bacteroides, often encode numerous parallel pathways for nutrient utilization. As a consequence, the genes encoding these responses are regulated at the local level and the global level. While the mechanisms of local gene regulation, often through the action of transcriptional regulators (hybrid two component systems, extra-cytoplasmic function sigma and anti-sigma factors, plus others) are better understood, the mechanisms of global regulation are still being unraveled. Several studies to date indicate that model species like B. thetaiotaomicron and B. ovatus possess “hierarchical” polysaccharide utilization behaviors in which more preferred nutrients are consumed first while less preferred nutrients are reserved for later growth after those with higher priority are depleted or gone. This behavior is similar to carbon catabolite repression in bacteria like E. coli but appears to occur through different mechanisms. These mechanisms, as well as the implications of this behavior in vivo in the gut, are being investigated in several projects.